Further observations on tuberculin reactions in active tuberculosis

Area of Science:

• Immunology
• Infectious Diseases
• Nutritional Science

Background:

• Tuberculin skin testing is a key diagnostic tool for tuberculosis.
• False-negative tuberculin reactions can complicate diagnosis.
• Protein depletion is a common sequela of severe illness.

Purpose of the Study:

• To investigate the cause of false-negative tuberculin skin test reactions in patients with active tuberculosis.
• To determine if protein depletion affects tuberculin reactivity.

Main Methods:

• One hundred patients with active tuberculosis were tested for tuberculin reactivity using multiple antigens (intermediate tuberculin, Tween-stabilized tuberculin, Tine test, mumps antigen).
• Skin reactivity was assessed within 24 hours of hospital admission.
• Patients received high-calorie, high-protein dietary supplementation for two weeks.

Main Results:

• 21-28% of patients exhibited false-negative tuberculin reactions upon admission.
• Non-reactors were clinically identifiable as seriously ill and protein-depleted.
• Skin reactivity was restored in most non-reactors after two weeks of nutritional supplementation.

Conclusions:

• False-negative tuberculin reactions in severely ill tuberculosis patients are likely due to impaired lymphocyte function secondary to protein depletion.
• Nutritional status significantly impacts cell-mediated immunity and tuberculin test results.
• The tuberculin test itself is reliable; observed non-reactivity reflects the patient's physiological state.